The result of calling it is something that can be encoded with the Python standard <a href="https://docs.python.org/3/library/json.html#json.dumps" class="external-link" target="_blank">`json.dumps()`</a>.

It doesn't return a large `str` containing the data in JSON format (as a string). It returns a Python standard data structure (e.g. a `dict`) with values and sub-values that are all compatible with JSON.

/// note

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="9"
{!> ../../docs_src/header_params/tutorial003.py!}
```

////

//// tab | 🐍 3️⃣.9️⃣ & 🔛

```Python hl_lines="9"
{!> ../../docs_src/header_params/tutorial003_py39.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="7"
{!> ../../docs_src/header_params/tutorial003_py310.py!}
```

## Managing hermetic Python

To make sure that TensorFlow's build is reproducible, behaves uniformly across
supported platforms (Linux, Windows, MacOS) and is properly isolated from
specifics of a local system, we rely on hermetic Python (see
[rules_python](https://github.com/bazelbuild/rules_python)) for all build
and test commands executed via Bazel. This means that your system Python
installation will be ignored during the build and Python interpreter itself

### Import `HTTPException`

```Python hl_lines="1"
{!../../docs_src/handling_errors/tutorial001.py!}
```

### Raise an `HTTPException` in your code

`HTTPException` is a normal Python exception with additional data relevant for APIs.

Because it's a Python exception, you don't `return` it, you `raise` it.

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="3  17"
{!> ../../docs_src/path_operation_configuration/tutorial001.py!}
```

////

//// tab | 🐍 3️⃣.9️⃣ & 🔛

```Python hl_lines="3  17"
{!> ../../docs_src/path_operation_configuration/tutorial001_py39.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="1  15"

Вона приймає об'єкт, такий як Pydantic model, і повертає його версію, сумісну з JSON:

//// tab | Python 3.10+

```Python hl_lines="4  21"
{!> ../../docs_src/encoder/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="5  22"
{!> ../../docs_src/encoder/tutorial001.py!}
```

////

所以接收上传文件，要预先安装 <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>。

例如： `pip install python-multipart`。

///

## 导入 `File`

从 `fastapi` 导入 `File` 和 `UploadFile`：

```Python hl_lines="1"
{!../../docs_src/request_files/tutorial001.py!}
```

## 定义 `File` 参数

创建文件（`File`）参数的方式与 `Body` 和 `Form` 一样：

```Python hl_lines="7"

Então:

```Python
q: Union[str, None] = Query(default=None)
```

...Torna o parâmetro opcional, da mesma maneira que:

```Python
q: Union[str, None] = None
```

Mas o declara explicitamente como um parâmetro de consulta.

/// info | "Informação"

Tenha em mente que o FastAPI se preocupa com a parte:

```Python
= None
```

Ou com:

```Python

A maioria dos frameworks Python existentes mais populares (incluindo Flask e Django) foram criados antes que os novos recursos assíncronos existissem em Python. Então, os meios que eles podem ser colocados em produção para suportar execução paralela mais a forma antiga de execução assíncrona não são tão poderosos quanto as novas capacidades.

Both *path operations* require an `X-Token` header.

//// tab | Python 3.10+

```Python
{!> ../../docs_src/app_testing/app_b_an_py310/main.py!}
```

////

//// tab | Python 3.9+

```Python
{!> ../../docs_src/app_testing/app_b_an_py39/main.py!}
```

////

//// tab | Python 3.8+

```Python
{!> ../../docs_src/app_testing/app_b_an/main.py!}
```

////